From owner-freebsd-standards@FreeBSD.ORG  Mon Mar  1 08:37:41 2004
Return-Path: <owner-freebsd-standards@FreeBSD.ORG>
Delivered-To: freebsd-standards@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP
	id B6DC616A4CE; Mon,  1 Mar 2004 08:37:41 -0800 (PST)
Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.86.163])
	by mx1.FreeBSD.org (Postfix) with ESMTP
	id EB56E43D39; Mon,  1 Mar 2004 08:37:40 -0800 (PST)
	(envelope-from phk@phk.freebsd.dk)
Received: from critter.freebsd.dk (localhost [127.0.0.1])
	by critter.freebsd.dk (8.12.11/8.12.11) with ESMTP id i21GbVJ4059774;
	Mon, 1 Mar 2004 17:37:32 +0100 (CET)
	(envelope-from phk@phk.freebsd.dk)
To: David Schultz <das@FreeBSD.ORG>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Mon, 01 Mar 2004 08:00:22 PST."
             <20040301160022.GA13617@VARK.homeunix.com> 
Date: Mon, 01 Mar 2004 17:37:31 +0100
Message-ID: <59773.1078159051@critter.freebsd.dk>
cc: stefan@fafoe.narf.at
cc: freebsd-standards@FreeBSD.ORG
Subject: Re: standards/62858: malloc(0) not C99 compliant 
X-BeenThere: freebsd-standards@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Standards compliance <freebsd-standards.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-standards>,
	<mailto:freebsd-standards-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-standards>
List-Post: <mailto:freebsd-standards@freebsd.org>
List-Help: <mailto:freebsd-standards-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-standards>,
	<mailto:freebsd-standards-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 01 Mar 2004 16:37:41 -0000

In message <20040301160022.GA13617@VARK.homeunix.com>, David Schultz writes:
>On Mon, Mar 01, 2004, Poul-Henning Kamp wrote:
>> In message <xzpznb0iwm0.fsf@dwp.des.no>, Dag-Erling =?iso-8859-1?q?Sm=F8rgrav?=
>>  writes:
>> >Poul-Henning Kamp <phk@FreeBSD.org> writes:
>> >> This is a deliberate choice.  Handling zero-size pointers correctly
>> >> in malloc(3) would be a rather involved and is currently not high
>> >> on the todolist.  A good patch might change that.
>> >
>> >The standard does allow returning NULL, you know.
>> 
>> Yes, but unfortunately that broke more software than I cared for
>> arguing with authors about.
>
>Several other malloc implementations do this, including the one in
>Tru64.  But assuming that there really are lots of broken
>applications out there, what's wrong with simply converting
>malloc(0) calls to malloc(1) calls?

I want to make sure people who malloc(0) and then deref the pointer get
the core dump they need to debug their problem.

But lets turn this around, do you have evidence of code which breaks
with the current behaviour ?  Does the code also fail if you give
malloc the 'V' flag ?

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.